PC making buzzing noise when I turn it on, but doesn't after I shut down and then boot up

[Carnivorex2]

Whenever I go to sleep I shut down my PC (custom built). When I wake up the next day, i go to turn it on. And I always know that there is going to be this loud buzzing noise. My temporary remedy for this is to just shut it down and boot it up again. By doing this, it fixes the problem. So what should I do to make sure this sound never happens at all? Is it my fans? Or my Hard drive? Or something else? Thanks.

 

[Xibyth]

Change the power supply, what your hearing is electrical buzz of the it's capacitor charging up. Back in the day when CRT (the fat) monitors were a thing they did that all the time. Usually this isn't a problem. I may be mistaken as I only have the description of the sound to go off, but if it isn't under load and just turning on this is usually the case.